diff --git a/src/newifc/root_window.c b/src/newifc/root_window.c
index 75d2cbb2ced14551c1c2f049d5d3b66557401a64..8e25098f128179fbbfc2fba02151f5d869b48be6 100644
--- a/src/newifc/root_window.c
+++ b/src/newifc/root_window.c
@@ -150,7 +150,7 @@ rw_get(NewIfcObj obj, int attr, ...)
 	return rw->api.last_error == NewIfc_error_none;
 }
 
-NewIfcObj
+static NewIfcObj
 rw_copy(NewIfcObj old)
 {
 	struct root_window *ret;